Here is Vidal the essayist at the height of his powersiconoclastic, witty, sarcastic, engaging, as he tilts at shibboleths of radicals and conservatives alike. Included in this gathering of 24 essays from the past six years are controversial pieces that have created a ruckus, such as his plea that the U.S. should make common cause with the Soviet Union against ``the Sino-Japanese axis,'' and his critique of the American pro-Israel lobby. Vidal portrays Ronald Reagan as ``a very sincere sort of liar,'' and is equally withering on Nixon and Oliver North. In literary essays, he strikes gold in discussing Henry James as book reviewer, William Dean Howells' avant-garde realism, Anthony Burgess's embrace of God and sex, Paul Bowles's underrated short stories and expatriate Quaker writer Logan Pearsall Smith, among others. In more personal pieces, he reminisces on the early history of aviation and gets culture shock in Mongolia. Reading Vidal is always an invigorating experience. (Nov.)